//
// Created by Yemao Luo on 2021/9/7.
//

#include <stdio.h>
#include <math.h>

int main(){
    struct Point{
        float x, y, z;
    };
    struct Point p1, p2;
    scanf("%f %f %f", &p1.x, &p1.y, &p1.z);
    scanf("%f %f %f", &p2.x, &p2.y, &p2.z);
    float dis = sqrt(pow((p1.x - p2.x), 2) + pow((p1.y - p2.y), 2) + pow((p1.z - p2.z), 2));
    printf("%f", dis);
    return 0;
}

